In general imaging, bone density measurement, or the like by radiation of an X-ray to a subject, a supporting tool is used as necessary. When the lumbar spine is to be measured, in general, the subject is laid face-up on an imaging stage. In this case, an orientation with bent knees of both legs is desired. In the orientation with the bent knees, the lumbar spine can be stretched out, resulting in a reduced degree of curvature of the lumbar spine. In the related art, in order to cause such a knee-bent orientation to be taken naturally; more specifically, in order to set an inclination angle of the thigh with respect to the bed surface to be an angle of greater than or equal to 45 degrees, a supporting tool dedicated for lumbar spine measurement such as a cushion having a trapezoidal or triangular cross section is inserted below the knee (refer to Patent Document 1).
When the femur is to be measured also, the subject is laid face-up on the imaging stage. In this case, it is desired that the legs be twisted such that the toes of the feet are rotated inward (toes moved close to the toes of the other foot). In order to create and maintain such a twisted orientation, a supporting tool dedicated for the measurement of the femur is used. The supporting tool has two inclined surfaces sandwiched between the legs. The inner sides of the legs are caused to contact the inclined surfaces, to achieve the twisted orientation of the legs. In order to maintain the twisted orientation, the legs are fixed by a belt or the like.
When an antebrachial bone (primarily, the radius) is to be measured, a supporting tool dedicated for the antebrachial bone measurement is placed on the imaging stage, which has a grip gripped by the subject (refer to Patent Document 2). With the use of such a supporting tool, the forearm is placed horizontally on the imaging stage. In this state, an X-ray is radiated onto the forearm.